Fix x86 real mode CS calculation #8521
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On x86 16-bit real mode, the CS varnode was re-calculated on every jump. However, due to the nature of how real mode works, it is impossible to reconstruct the value of CS at those points. Luckily, the correct value of CS seems to be set at the beginning of the function by auto-analysis in real mode, so if we don't change it, it should be correct throughout the function. Also change the definition of some of the "CALLF" instructions to ensure the correct value of CS is restored after the call.
GhidorahRex
added
Type: Bug
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Fixes #6694
On x86 16-bit real mode, the
CSvarnode was re-calculated on every jump. However, due to the nature of how real mode works, it is impossible to reconstruct the value ofCSat those points. Luckily, the correct value seems to be set at the beginning of the function by auto-analysis in real mode, so if we don't change it, it should be correct throughout the function.This PR also changes the definition of some of the
CALLFinstructions to ensure the correct value ofCSis restored after the call.I've personally barely tested this patch, and I don't really have experience with x86 reverse engineering, but this patch seems to help people in the aforementioned issue, so I figured I'd add it as a real PR.